Automatic gun charger



1945- e. w. PONTIUS, 313., ET AL 2,413,112

AUTOMATI C GUN CHARGER Filed Dec. 26, 1940 5 Sheets-Sheet 1 INVENTORS soeas I44 PomvusZZZ Ae-rHue P. MASON Dec. 24, 1946. e. w. PONTIUS, 30., ET AL 2,413,112

AUTOMAT IC GUN CHARGER 5 Sheets-Sheet 2 Filed Dec. 26, 1940 INVENTORS 650265 144 Paw-m5 Z27 AETHUE P. WILSON 5 Sheets-Sheet 5 G. W. PONTIUS, 3D., ET AL AUTOMATIC GUN CHARGER Filed Dec. 26, 1940 Dec. 24, 1946.

INVENTOHS Pom r/usfl GEORGE W. By AQTHUE FE WILSON l atentecl Dec. 24, 1946 =UNlTED STATES PATENT ldli Frrc

AUTOMATIC GUN CHARGER Delaware Application December 26, 1940, Serial No. 371,742

11 Claims.

This invention relates to guns, and more particularly to an automatic system for charging guns.

In many types of guns the loading operation is performed by the reciprocation of a breech bolt. This is particularly true of automatic guns such as machine guns or automatic cannon. In automatic guns the reciprocation of the breech bolt is accomplished by power developed by the firing of a shell, and the firing of one shell ejects its empty cartridge and places the succeeding shell in the gun breech ready for firing. If, however, one of the shells is a dud and fails to fire there is no reciprocation of the breech to eject the dud and insert a fresh shell. Such a gun is described as a jammed gun, which gun is thereafter unable to fire automatically. Also, the moving parts of an automatic gun may become stuck or pinched so that they are unable to operate automatically and such a gun is also termed a jammed gun. In any event, the only way to place a jammed gun in an operating position is to reciprocate the breech bolt by auxiliary means. I

In the past it has been customary to reciprocate the sliding parts of a jammed gun by hand. When the gunner is remote from the gun, as the pilot of an airplane having guns in the wings, cables and other operating mechanism have to be supplied for this purpose. There are several drawbacks, however, to hand freeing of a jammed gun. In the larger calibre guns and cannons now in use it is very diflicult to reciprocate the moving parts manually. Further, if the gunner has other duties, as has the pilot of an airplane, he cannot take the time and effort necessary to manually free and charge the gun. These and other considerations make it desirable to have a power mechanism for charging guns,' and this mechanism is most desirable when operated automatically.

Attempts have been made to provide power systems to charge guns by using various pneumatic power systems. Some of the pneumatic systems are automatic using electrical controls to create an automatic action. Invariably, however, in these systems there is a mechanical time lag mechanism, such as a dash pot, which is reset at every shot of the gun. If the gun should fail to fire for a given period of time the dash pot will travel through its stroke and set the charging system in action.

Our invention improves upon the prior art in that it uses hydraulicfluid rather than a pneumatic fluid as the power medium for charging guns; Hydraulic fluid has been found to be more tinctly novel.

' ammunition or is in some way defective.

reliable and positive in action and therefore is preferred over pneumatic systems. There are many special problems involved in the use of a hydraulic fluid as compared toa gaseous fluid.

Whereas a gaseous fluid may be exhausted to art in that electrical controls completely regulate the hydraulic charging system. The electrical control circuit is believed to be an improvement over any prior device and is believed to be dis- In our invention, the time lag mechanism is electrical, thereby saving weight. Also; when compared to a dash pot, there is an increase in service life as a dash pot is subject to abusive operation at every shot. The various parts of the system are particularly designed for a hydraulic system, to accommodate the peculiarities of flow of a hydraulic fluid. In addition to the above, according to one very important feature our invention incorporates a selector valve mechanism for charging several guns from a single master valve.

There are many important parts to the invention. These include a specially designed charging cylinder for hydraulic fluid. Also, special brackets are provided to hold charging cylinders to the guns. We further provide charge counting devices to limit the number of charging operations of a gun, as a gun requiring a large number of such operations has probably expended its Means are provided whereby the armorer of a gun may reload'the gun with afresh belt of ammunition or test the operation of a gun when it is equipped with our charging system. Also, we provide a cut-out means for stopping runaway guns, which might otherwise be injured by a long burst of fire. I

It is therefore an objectof our invention to provide an electro-hydraulic charging system which is fully automatic.

It is a further object of our invention to provide an automatic charging system which meets all conditions and requirements of operation of a gun.

Another object of our invention is to provide a charging system for several guns, wherein selector valves direct hydraulic fluid from a single master valve to the particular'guns requiring charging.

Another object of the invention is to provide 3 a quick acting solenoid-operated hydraulic valve, having a positive seal in the closed position and operable by a small electric current.

Another object is to provide a charging cylinder for use with hydraulic fluid.

Another object of the invention is the provision of means whereby the armorer of a gun equipped with our invention may reload a gun with a fresh belt of ammunition or test the operation of the gun.

Another object is to provide charge counters which cut out a charging system after a predetermined number of charges.

Another object is to provide means to stop runaway guns which fire regardless of trigger actuation.

A feature is to provide special brackets for holding a charging cylinder to a gun, which brackets may be quickly opened to remove a charging cylinder from a gun.

Other objects and features of the invention will be apparent in the following description and claims which may best be understood when considered in connection with the following drawings, in which:

Figure 1 is a diagrammatic plan view of the entire automatic charging system as applied to a pair of machine guns;

Figure 2 is a diagrammatic plan view of a modified form of an automatic system employing selector valves for each charger;

Figure 3 is a view in vertical section of a charging cylinder and a cooperating switch and mechanical charge counter forming a part of our invention;

Figure 4 is a fragmentary outline view showing the switch of Figure 3 in an inoperative position;

Figure 5 is a vertical section along the lines 5-5 of Figure 3 showing the construction of a clamp which holds the charging mechanism to a gun;

Figure 6 i a view in longitudinal section of the solenoid-operated hydraulic'valve used with the system; and

Figure 7 is an end View of the piston of the charging device.

Description of the system of Figure 1 The embodiment of our invention shown in Figure 1 will first be described. Two guns 2] are the guns controlled by the accompanying electrohydraulic system. Although two guns are shown to disclose the application of the invention to a plurality of guns, the invention is equally applicable to a single gun. Also, the invention can be used to control a larger number of guns, and this is implied from the application of the invention to two guns as in Figure 1. The guns may be on an airplane in a turret, or placed in the wings. Or the guns may be in a tank, ship or land fortification or any other place where guns are needed. The use and application of the guns forms no part of the invention.

Our invention employs a hydraulic charging circuit operated by electrical controls. Hydraulic fluid is stored in'a reservoir l and flows from there to a pump l2 which forces hydraulic fluid under pressure into an accumulator M, which charges high pressure line IS with high pressure fluid. Low pressure line I returns exhaust fluid to the reservoir. The fluid flowi regulated by solenoid operated valves 18 which direct hydraulic fluid through conduits H to charging cylinders 2!]. The hydraulic fluid acting in cylinders 20 charges the guns 2! to which the'cylinders are 4 attached, and when the charging stroke is completed valves 1 8 automatically exhaust the charging fluid, completing the charging stroke.

The electrical controls are designed to meet the many requirements of military operations. If during a firing period, a gun becomes jammed, the charging cylinder 20 must be operated to once more place the gun in an operative condition. If the charging cycle is started and the firing period is ended, the charging should nevertheless be continued so that the gun will be ready to fire the next time the trigger is actuated. In the event that agun starts firing continuously because of some defect, regardless of trigger operation, the charging mechanism must be operable to charge the gun to prevent the runaway gun from being injured, or from firing indiscriminately. Another contingency that must be provided for is that of a defective gun which will not fire. If such a gun were charged repeatedly during the firing period it might reduce the fluid pressure available, and means must be provided to cut out the charging mechanism after a given number of strokes. These and other contingencies are all provided for in our system here described.

The electrical circuit of Figure 1 will now be described, and for purposes of simplification will be described with relation to one gun. Corresponding circuits having the same reference numerals can be traced for the other gun. Electrical current under a potential may be derived from any suitable source, but as illustrated, a storage cell 22 is employed. The current passes to an ignition switch 24, which which closed passes current to a slow release relay 26 by means of an electrical conductor. A branch of this electrical conductor passes current to switch 34, which when closed passes current through an electrical charge counter mechanism 300 and through that unit to solenoid valve l8. Thus when switch 24 is closed, current will pass to switch 34, which when closed will pass current to the hydraulic valve I8 which will cause the hy- 1 draulic charging mechanism to operate.

The control of the charging mechanism is effected by making and breaking switch 34, and the electrical circuits to accomplish this end will now be described. The circuit through slow release relay 26 has two branches leading to ground.

Interposed between the relay 26 and the branches is a manually operated switch 3!. One ground branch for relay 26 is through the switch 38 placed at the rear of the gun. Switch 38 is normally open, but is closed by a breech pin on the breech bolt of the gun 2|, when the breech bolt reciprocates in the gun. The breech bolt reciprocates in the gun during automatic firing, or when the charging mechanism retracts the breech bolt of the gun in a charging cycle. The other branch ground circuit for relay 26 is througha normally open type of switch 28, which is held closed by the breech bolt when it is in its forward positionof the gun, and through switch 30 which is normally closed. Switch 28 is at the forward end of the path of reciprocation of the breech bolt of the gun 2 I. The breech bolt pin will keep switch 28 closed whenever the breech bolt is closed, but when not closed by the breech bolt it tends to open. Thus, when the breech bolt is closed there will normally be a groundcircuit for relay 26 through switch 28 and 30:Grounding relay 26 energizes its solenoid 21, which actuates a bell crank 29 to'open switch 34; cutting oif any current to valve I 8. Thu when switch 24 is aiiaiia closed, and the breech bolt oi the gun H is closed,

the relay 26 will be grounded and will actuate. bell crank 29 to open switch 34 before any ap-- preciable amount of current can reach the valve I8. The only eiTect then of closing switch 24 will be to open switch 34 when the breech bolt is in a closed position.

Closing switch 24 also passes current to one contact of safety or combat switch 40. When safety or combat switch 40 is closed current is passed to one contact of trigger switch 42. Closing trigger switch 42 passes current to a solenoid operated trigger actuator 44 mounted on the gun 2 I. This trigger actuator will actuate the trigger of the gun 2i and cause the gun to fire if there is a live shell in the firing chamber. Closing trigger switch 42 also passes current to a solenoid 46 which acts through a bell crank to open switch 30 in one of the ground branches of relay 26. Thus, when trigger switch 42 is closed the ground circuit of relay 26 through switches 28 and 30 is broken at switch 30, and the solenoid 21 of relay 26 starts to lose its energy. However, relay 26 is a slow release relay and will hold the bell crank 29 to keep switch 34 open, during the particular time period for which it is constructed. This period can be any period longer than the time between shots of gun 2I when firing automatically. Wherrthe breech bolt upon firing reaches the rearward end of its stroke, the breech pin touches a switch actuator 33 to close switch 38,

grounding relay 26 through this circuit which again reenergizes the soleniod 21 of relay 26. This intermittent energization of relay 23 through switch 38 maintains switch 34 in an open position so that valve I8 will not be operated.

If the gun should jam, however, relay 26 would not be intermittently energized through switch 38, and at the expiration of the time period necessary for it to lose its energy it will release bell crank 23 closing switch 34 and passing current through the counter 300 to the valve I8, actating the hydraulic charging mechanism. When the charging mechanism moves the breech bolt to its most retracted position, switch 38 is again closed and current passes through solenoid 2'! of relay 26. The solenoid 21 then attracts one arm of hell crank 29 to again open switch 34 and deenergize solenoid valve I8 causing itto close and communicate the charger 20 to exhaust. When the breech bolt again closes the gun will continue to fire automatically. 1

If a charging cycle should be started and the firing period then terminated, the gun will nevertheless continue to charge. When the firing period ceases solenoid 43 will be deenergized, allowing switch 30 to close, thus closing one link in one ground circuit of relay 26. However, as soon as the charging cycle starts switch 28 opens, thus opening the only possible ground circuit and the charging operation will continue until switch 38 is closed at the end of the charging movement.

Thus one purpose of switch 23 is to continue a -counter 300 comprises a plate member 302 having a conductor sector and having notches along the edge of another sector. The member 302 is pivoted at 306 about which point it rotates. Brushes 304 contact the conductor sector of the member" 302. A ratchet arm 308 is also attached to pivot 30B and has a catch 3| 0 pivotally secured thereto, contacting the notches of the member 302. A solenoid 3I2 receiving current from the main line to valve I8 is placed adjacent to the other end of ratchet arm 308. Every time the valve I8 is energized, current passes through the solenoid 3I2 to ground, and solenoid 3I2 acts on ratchet arm 308 to cause rotation through a small arc. The catch 3l0 on lever arm 300 contacts the notches of member 302 to rotate that member through a corresponding arc. In the meantime the main current passes through brushes 304 and through:

the conductor portion of member 302 to energize valve I8. After a predetermined number of charges, a conductor sector of the member 302 will rotate out of contact with the rearward brush 304, and thus effectively break the circuit to valve I8. In this way a gun which has expended its ammunition or which repeatedly jams, will not be charged after a predetermined number of charges have already been made.

Switch 3I is manually operable by means of a handle placed on one member of the switch. By holding switch 3| open current cannot pass through relay 23 and any energy therein wi11 be dissipated thus closing switch 34, effecting a charge as described above. By means of switch 3| the gunner may charge any gun if he has any reason to doubt that it is not in an operative condition, or if there is a runaway gun this gun may be effectively stopped by opening switch 3 I, which also causes any gun to be charged. By holding switch 3! manually open the associated gun will charge and the breech bolt will be held in a retraoted position, and if the object in so doing is to cool off a runaway gun this switch can be kept manually open until such a gun is cooled to the point where another burst of firing will not injure the gun.

A ring 23 is provided for actuating one member of switch 28. This ring is used by the armorer when reloading the gun with a new belt of ammunition. The old belt of ammunition is first manually removed from the gun. By pulling on ring 23, the ground of relay 26 will be broken, and if the pull is of a duration long enough to allow relay 26 to deenergize before reelasing ring 23 current will thereby pass to the solenoid of valve I 8 to effect a charge which will eject the live shell n the firing chamber. The first link in a new belt 18 then inserted in the feedway of gun 2| and ring 23 again pulled as before, allowing the gun pawl to engage the first live round. Following these operations, one more charging cycle must be per- Description of the system of Figure 2 The selector valve system shown in Figure 2 will next be described. The selector valve system differs from that of Figure 1 in that each charging cylinder 20 has a selector valve I I0 controlling ;'fluid. flow from a single master valve I8. The selector valves I III are connected to a common bydraulic iiuid line I 9 controlled by master valve I8 and are selectively opened to charge the proper gun. The selector valve system is used to eliminate the weight for each charging cylinder of a separate hydraulic valve strong enough to control fluid under full pressure. The selector valve I I is opened only when there is no fluid pressure in the line to the charging cylinder 20, and therefore can employ a very small and lightweight solenoid In some installations there is a saving of weight by the use of selector valves, making the system very desirable in such installations, as in aircraft. 7

The electrical circuit for the selector valve system is basically the same as that for the directly operated system. Closing switch 24 passes cur-' rent to relay 26, which as in Figure 1 has two ground circuits, one through switch 33, and the other through switches 28 and 130. Solenoid 21 when energized acts through a bell crank IIB to open switch 6 3 to master valve I8 in much the same way as in Figure 1. Bell crank II3 differs from bell crank 29 of Figure 1, however, in that it is a conductor of current, passing current through its length when switch 35 closes. The other end of a bell crank H8 also forms a part of a switch 20 at the same timeit operates a switch 34. When solenoid 21 of relay 25 is deenergized, and'bell crank IIB is released, current flows from switch 34 to master valve I8 and in addition through bell crank M8 to switch I20, and through a conductor to the solenoid III of selector valve H0. Thus when the solenoid 2I.is deenergized, current is passed to selector valve H0, and to master valve I3.

The selector valve III} is a simple solenoid lift valve or poppet valve of any suitable construction. The solenoid II I employed is so small, that means must be provided to insure that there will be no pressure on the line I9 when it is operated as any interfering forces cannot be overcome by the selector valve solenoid III. This means includes a switch I54 for grounding the master valve I 8, which switch is operated by the opening movement of selector valve IIG. A movable valve core H2 or solenoid valve IIO actuates a bell crank H6, the opposite end of which opens and closes the switch I I4 which grounds master valve I8. This construction insures that selector valve H0 will always be open before fluid under pressure is directed to it by master valve IS.

The selector valve ystem employs'mechanical charge counters, and these will be next described along with the charging cylinder 26. The electrical counters 36d of Figure 1 could also be applied, and could be inserted in the selector valve circuit with equal effect. The mechanical charge counters could also be applied to the system of Figure l, with equal effect.

Description and operation o the device of Figures 3 and 4 The charging cylinder .25 used with the systems of Figures 1 and 2 i shown in detail in Figures 3 and 4 and will next be described. Although this charging unit is well suited for the automatic systems here described, it is applicable to any type of gun charging system and is not limited to any specific system. The unit may be used on a manually controlled system, and for such use none of the electrical features of the present systems would be used. A manually controlled system in which this unit could be used is described in the copending application by White and Pontius Serial No. 311,978, filed January 2, 1940. The charging cylinders can also be used in a semi-automatic system such as described in an application by Pontius Serial No. 319,925, filed February 20, 1940. Other uses and applications of the charging unit can be made, and we do not intend to limit its use to the present systems.

The cylinder unit 25 comprises a cylindrical casing I50 within which a cylindrical piston I52 reciprocates. toward the front of the gun on which it is mounted, and the left end of the unit is secured tov the rear of the gun. The piston I52 is provided with means such as a lu I53 which contacts a breech pin I84 (shown in dotted outline) and moves the breech bolt of the gun 2I rearward by acting on breech pin I84 during a charging stroke. The cylinder I50 is slotted at I5I to accommodate the lug I53 which reciprocates with the piston. Fluid flow is directed into the cylinder I50 by a fitting I54 which may be connected to either a selector valve III) as in Figure 2 or directly to the valve line I8 as in Figure 1. The cylinder I56 is held to the gun by a forward bracket I 55 and a rear bracket I 58.

The piston I52 is held in a forward position by a compression spring I60 which fits inside cylinder I55 and extends into piston I52. The spring I60 is mounted on a two-part tubular telescoping spring guide. One part of the spring guide is an outer member I62 which is secured.

to the cylinder I50 by a fitting I64 at the rear end of cylinder I50. The other part of the spring guide is an inner tubular member I66 secured to the piston I52. As the piston I52 reciprocates within cylinder I50 under the influence of hydraulic fiuid and the return spring I65, the inner member I56 secured to the piston I52 telescopes in the stationary outer member I62.

A'pointed pin I68 slides in guide member I62 and has an extended shank I10 which passes through a constriction in the inner end of guide member I66, and has a head IE2 attached to the end of the shank. The relationship of parts is such that the last portion of the rearward movement of piston I52 causes the inner telescoping,

the piston I52 has returned nearly to its starting position, giving the breech bolt a free path of travel. The breech bolt catch includes a rocker arm I14 pivoted at I15 to the rear support bracket I58. It comprises a forward end I16, and a rearward portion I18 connected by an intermediate portion I19. On the forward end I16 of the rocker arm I14 is a catch finger I16a pivoted at I16?) and urged by a leaf spring I160 to a catch position. On the rear end I13 of the rocker arm I14 is a roller I180. designed to reduce friction when the rocker arm is contacted by the pin I68. Also secured to the rear end I10 of rocker arm I14 is a leaf spring I50 contacting the bracket I 58. The leaf spring I normally maintains the rocker arm I14 in a disengaged position. The fitting I64 on the rear end of cyle inder I50 has secured thereto a roller I82 to pro- The right hand end of the unit is vide a-thrust bearing when the pin I68 strikes rocker arm roller I18.

The operation of the charging unit as thus far described is as follows. Charging fluid from any suitable control device, manual or automatic, flows through fitting I54 into the cylinder I58. The fluid under pressure forces piston I52 to the left and in doing so the breech bolt of the gun is moved backward through contact of piston I52 with the breech pin I84, shown in dotted outline.

As the piston I52 nears the end of its stroke, the guide tube I56 strikes the end of pin I68 forcing it between rollers I82 and I18. This movement of the pin I68 forces the rocker'arm I14 to move against the compression of spring I66 to assume a nearly horizontal position. In that position the latch I18 is in the path of the breech pin I84 as shown by the dotted outline of latch I16. As the breech pin nears the end of the charging stroke, it strikes the latch I16 and causes it to rotate about its pivot against leaf spring I15c allowing the breech pin 84 to pass. Once the breech pin is past the latch I16 the spring I160 causes the latch to snap back to its normal position, locking the breech pin in its retracted position. 7 v

When the charging cylinder reaches the end of its stroke the charging fluid is cut off from pressure and ported to exhaust, either auto matically or manually. Spring I60 now forces the piston I 52 to its starting position, forcing out the fluid to exhaust. The latch I16 on rocker arm I14 holds the breech bolt through pin I84 in a retracted position until the piston I52 is out of the path of travel of the breech pin I84 so as to allow the breech bolt to have an unimpeded action on the closing stroke. The release of the breech pin I84 is accomplished by pulling pin I68 from between rollers I82 and I18, which removal allows rocker arm I14 to rotate about its pivot to render the latch I16 inoperative. The pin I68 is pulled from between the rollers by the restriction of tube I 66 striking head I12 on shank I of pin I68 as the piston I52 is moved to its starting position by spring I60. the pin I68 is pulled out from between rollers I18 and I82 only when the piston I52 has retracted out of the path of travel of breech pin I84. As described, the device is a charging unit which will hold a breech bolt in a retracted position until the charging piston has withdrawn from the path of travel of the breech pin.

The charging unit as applied to the systems herein described incorporates further features. The actuator switch 38 is also shown in detail in Figure 3. This switch is operated by the switch actuator 36 which is secured to the bottom side of switch 33. At every reciprocation of the breech bolt, whether during automatic firing or during a charging cycle, the breech pin I84 strikes the switch actuator 36 which in turn closes the switch 3811. It will be noted that the switch 38a is of the snap spring type wherein a small movement on one part causes a. movement in the opposite direction of the contacts to close the switch 380.. f

The charging unit as shown incorporatesa mechanical charge counter. Mounted on the rear bracket I58 is an ar I90 supporting a rotatable ratchet wheel I92 which has a segment removed, and a reciprocable spring pressed push button I94. A strip of spring metalv I96 is attached to the upper end of the push button and The push butcontacts the ratchet Wheel I92.

The arrangement of parts is such thatton I94 extends into the path of travel of pin I68. At every charging stroke of the charging unit 20 the pin I68 strikes the push button I04 causing it to move upward against the compression of its spring. This causes a rotation of the ratchet wheel I82.

The actuator switch 38 is rotatably secured to the bracket I58 by means of pivot pin I08. Pro- .truding from the rearward side of the pivot cut out a charging unit 20 from the hydraulic circuits when a predetermined number of charging operations have been made. An excessive number of charging operations indicates that a gun has expended its ammunition or is defective and in any event can not fire normally, and therefore should be out out from the hydraulic circuits so as not to reduce hydraulic pressure unnecessarily.

The operation of the mechanical charge counter is as follows. At every charging stroke the ratchet wheel I92 will be rotated one notch by the spring metal strip I96 attached to the push button I94 when it is contacted by pin I68, and after a given number of movements, for example seven, the ratchet wheel I92 will be rotated so that the relieved portion or segment is adjacent the finger 200. When the relieved portion reaches the finger 200 the spring 202 causes the entire switch unit 38 to rotate in a clockwise direction, to the position shown in Figure 4. When in this position the switch actuator 36 is beyond the reach of the breech pin I84 and the switch 38a remains continuously in a closed position. To return the gun to normal operation, the ratchet wheel I92 is manually rotated to its starting position, causing switch 38 to once more assume an operative position as shown in Figure 3.

The switch 28 is also shown in Figure 3, and is shown as housed in casing. Switch 28 is operated by a switch operator 28a, similar to operator 36 for switch 38. This operator is contacted by the breech pin I84 in the breech bolt of gun 2i, whenever the breech is closed on the firing chamber.

Description of the device of Figure 5 Another part of our invention relates to the brackets I56 and I58 for holding the charging unit to the gun. As shown in Figure 5 which is a section through the rear bracket I58 the bracket is of a type which may be opened to remove the charging cylinder I50 and its internal mechanism from the gun 2I. A semicircular locking member 204 is pivoted to the bracket I58 at 206. A clamp member 208 is hinged to the bracket I58 at 2I0, and acts through screw 2I2 to clamp the locking member 204 around the fitting I64 of the charging cylinder I50. When it is desired to dismount the charging cylinder I50, screw 2I 2 is unloosened, the clamp swung downward and the locking member 204 swung upward. In this way the charging cylinder I50 may be unfastened from the gun and the gun removed without disconnecting the hydraulic circuit. This type of bracket is desirable for removing a gun from its emplacement for repairs, cleaning or replacement, which operations may be performed without disconnecting any hydraulic circuits.

Description and operation of the device of Figure 6 Another part of our invention relates to the solenoid operated master valve 18 used with our automatic systems. This valve is of the pilot valve type, wherein the fluid pressures controlled are applied by a small pilot valve for opening the main valve. The valve I8 is shown in detail in Figure 6 which is a sectional view of the entire mechanism. The valve is comprises a casing 220 having an inlet port 222 and an exhaust port 224, which are selectively communicated by the valve mechanism to an operation port 226. A cylinder 228 closed at one end is secured to the left side of the casing 220 by an annular nut 230. A solenoid unit 232 is secured to the cylinder 228 by a bolt 236 acting through nut 234 placed inside of cylinder 228. A main valve member comprises a sleeve 238 which is centrally slotted to form communicating openings. The end of the sleeve toward the solenoid 232 is enlarged as at 24! to form the large sleeve 24!, and seats on the casing 220 adjacent to the inlet port 222. A small passage 242 continuously communicates the interior of the large sleeve 24l with inlet pressure, causin cylinder 228 to be filled with liquid.

A pilot valve is provided for valve l8, and the pilot valve when actuated by a relatively small magnetic effort, applies the principal fluid pressure to open the main valve, which requires a relatively large eilort. The pilot valve comprises a needle valve 244 reciprocably mounted in the enlarged end 24! of sleeve 238, and is normally seated against the mouth of a passage 245 formed adjacent to the enlargement 240 and communicating sleeve 238 with enlarged sleeve 24L The needle valve 244 is urged toward its seat by a. conical spring 245 seated on cylinder 228. Passage 245 is larger than passage 242. The needle valve 244 is slidably held in sleeve 24!! by a transverse pin 248 traversing a slot in needle valve 244. The needle valve body 244 is fluted to allow the flow of fluid past it. A stem 250 is pinned to pilot valve 244, and a fluted hammer member 254 is axially I mounted thereon, and free. to slide axially. A head 252 on the end of stem 253 holds a weak spring 253 under compression against fluted hammer 254. Fluted hammer 254 moves alon stem 258 against the compression of weak spring 253,

when solenoid 232 is energized, and strikes head 252 of stem 25B, pulling pilot valve 244 off of its seat.

The operation of solenoid valve I 8 is as follows. The position of the parts of the valve I8 under normal conditions is shown in Figure 6. Sleeve 238 communicates operation port 226 with exhaust port 224. The enlargement 240 of sleeve 232 is seated against the casing 220 eifectively sealing ofi high pressure port 222. Pilot valve 244 is seated on the mouth of passage 24!) and prevents leakage into sleeve 238, High pressure fluid enters passage 242 and fills the interior of enlarged sleeve 24 l, the portion of casing 220 behind or to the left of sleeve 24!, and the interior of cylinder 228. The full fluid pressure available at port 222 is exerted on the fluid inside the valve, through passage 242, and the fluid presses against the end of cylinder 223 and against the sleeve 238 to efiectively force enlargement 240 of sleeve 238 12 against its seat in casing 220. Spring 253 forces fluted hammer 254 toward the right.

When the solenoid 232 is energized by any means including the charging systems which have been described, it attracts fluted hammer 254 to ward the left. Hammer 254 compresses weak spring 253 and then strikes violently against the head 252 of stem 253 unseating pilot valve 244 against the compression of spring 245. Thehigh pressure fluid within the. sleeve 244 then flows through passage 245 to the exhaust pressure in the right hand side of the valve casing 229. Since passage 245 is larger than passage 242, the pressure inside enlarged sleeve 249 will drop and become greatly less than the pressure in port 222. High pressure fluid in port 222 will now act on the enlarged sleeve 244, throwing it rapidly to the left, allowing the slots in sleeve 238 to communicate high pressure port 222 with operating port 226. The same movement of sleeve 228 closes off exhaust port 224. Fluid will now flow from port 222 to operation port 223 and the operated mechanism connected thereto. When it is desired to close the valve, the solenoid 232 is deenergized, and fluted hammer 254 is no longer attracted to the left. Spring 246 then seats pilot valve 244, which causes pressure to build up behind it, as passage 242 is at all times in open communication with port 222. The fluid under pressure within the left portion of the valve l8 forces the enlarged sleeve 24S against its seat on casing 223, effectively cutting off the flow of high pressure from port 222 to port 225. The same valve movement communicates exhaust port 224 with operation port 226, through the slots of sleeve 233. Spring 253 forces fluted hammer 254 to the right, and the whole valve is once more ready to be operated.

The valve I8 just described is very important where weight is a factor to be considered, as in aircraft use. By means of the pilot valve, 3, very small electro-magnetic force can be used to control and operate a poppet type valve subject to ,high pressures. The use of a small electrc-magnetic force allows the use of a very small and lightweight solenoid as compared with the relatively huge solenoid which would be required for direct operation. In the control of high pressures, it is important to use a poppet type valve as contrasted to piston type valves, as a. poppet type valve is self-seating and self-sealing. It is believed that the pilot valve control and operation of a poppet type valve which has been disclosed is novel and constitutes a distinct improvement in the art.

Operation of the system 0 1 Figure 1 The operation of the system shown in Figure 1 is as follows. The hydraulic pump 12 is operated by any suitable source, and pumps hydraulic fluid from reservoir In to accumulator l4. The pressure conduit l6 becomes filled With fluid under pressure and the exhaust conduit l5 becomes subject to exhaust pressure. Solenoid valves 18 are now ready to direct hydraulic fluid to conduits if! when operated by the electrical circuit. Conduits l9 direct the fluid from valve I8 to the charging cylinders 20 to charge guns 2 I.

The operation of the electrical circuit will now be described with relation to one gun 2!, as the operation is identical for the other gun 2 l. Ignition switch 24 is first closed, passing current to slow-release relay 26 which is normally connected through manual switch 3 I, which is normally closed, and through switch 28, which is normally 13 closed by the breech bolt when the breech of the gun 2| is closed and from there through switch 30 which is normally closed when the gun is not firing, and is there grounded. Grounding this circuit energizes the solenoid 21 of relay 26, which acts throu h bell crank 29 to open switch 34, thus cutting 01? current to solenoid valve I8. When it is desired to fire the gun, safety switch '40 is first closed, and then trigger switch 42 is closed. The trigger solenoid 44 is operated by the current from switch 42 and the gun begins to fire. At the same time solenoid 46 is energized, which breaks the ground of relay 26 at switch 30.

When the ground relay 26 is broken at switch 30, there is a tendency for the solenoid 21 of relay 26 to release the bell crank 29, closing switch 34. However, relay 26 is a slow release relay having a release period greater than the interval between shots of the gun to which the charging mechanism is afiixed. Since the same switch operation that breaks the ground of relay 26 at switch 30 also energizes the trigger actuator 44, the gun 2| will fire at the same time switch 30 is broken, and the breech bolt reciprocates, alternately closing and opening actuator switch 38. Closing switch 38 grounds relay 26, energizing solenoid 21 so that it will continue to maintain switch 34 in an open position.

H the gun jams during a firing period actuator switch 38 remains continuously open because the breech bolt will not reciprocate, and the solenoid 21 of relay 26 becomes deenergized at the end of its time period causing switch 34 to close.

Solenoid valve I8 then opens, passing fluid to the hydraulic charging cylinder 20 which charges the gun by retracting the breech bolt of the gun, ejecting the dud shell and inserting a fresh one. When the breech bolt reaches its most retracted position it acts on operator 36 to close switch 38, thereby grounding relay 26 and breaking the connection to solenoid valve I8. If the trigger system is still in a firing condition the gun will once more fire upon the breech bolt closing and contacting the cartridge chamber.

If the firing control is cut off during the charging stroke it is desirable to continue the charging operation so that a fresh cartridge will be in the firing chamber for the next firing period and this operation is as follows. Upon cessation of firing, solenoid 46 is deenergized and switch 30 is thereby closed. Relay 26 is not grounded, however, as the first movement in the charging cycle forces the breech bolt backward opening switch 28. Because switch 28 is open the ground of relay 26 is broken during the charging cycle until the breech 'bolt reaches the end of its reoiprocatory movement, at which time relay 26 is grounded through actuator switch 38, and valve I8 is thereby closed. The charging operation inserts a fresh shell in the firing chamber and the gun is once more ready for firing when the trigger is actuated, Often when a period of fire is over it is desirable to reload the machine gun 2| by inserting a fresh belt of ammunition into the mechanism of the gun. The old belt is removed from the gun and a new belt inserted into the gun. The charging operations necessary to place a cartridge of the new belt into the gun can be performed by the charging system. Thearmorer pulls on ring 23, opening switch 28, breaking the connection to ground for relay 26. If ring-23 is pulled to keep switch 28 open for a period longer than the time .interval of relay 26, the deenergization of relay '26 will release bell crank 29 closing switch 34, .which actuates valve l8, charging the system.

-The first charging stroke ejects the live shell in the firing chamber. The first link in a new belt is then inserted in the feedway of gun 2|, and ring 23 is again pulled, allowing the gun pawl to engage the first live round. Following these operations, one more charging cycle must be performed before the gun will fire. This charge is usually performed by the gunner, just prior to combat by manually opening switch 3|.

This charging sequence is followed to provide an added safety feature inasmuch as the gun cannot be fired until this final charge is made.

The electrical charge counter 300 cuts out a gun which requires an excessive number of charges, as such a gun is probably defective, and the operation. is as follows. At every charge, solenoid 3|2 is energized, pulling on ratchet arm 308 which in turn rotates conductor member 302 about its pivot 300. The current meantime flows from brushes 304 through conductor member 302 to operate valve [8. After a predetermined number of charges have been made, the ratchet has rotated conductor member 302 out of contact with the forward brush 304. In this position of member 302, current can no longer pass to valve I8, and thereafter when gun 2| jams it will not be charged, but will remain in a jammed condition. Charge counter 300 can be reset manually to start through its cycle of operation.

In firing a gun it sometimes happens that a part will become stuck or injured so that a gun will continue to fire regardless of trigger actuation. Such a gun is known as a runaway gun. Our invention provides-means to control such guns to keep them from becoming injured by long continued fire. This means is the manually operated switch 3| illustrated as'near rela 26. By manually opening switch 3| the ground connections of relay 26 are all disconnected and switch 34 closes passing current to solenoid valve I8 causing it to charge the gun 2|.

Often a single charge is enough to restore a runaway gun to normal operation, but where this is not suificient the breech bolt of the gun can be held in a retracted position by keeping switch 3| open until the gun is cooled to a point where further runaway firing will not injure it. The switch 3| is shown adjacent to the gun, but by using longer conductors the switch 3| could be placed near the other manually operated switches 24, 40 and 42.

Operation of the system of Figure 2 sired to fire the gun, safety switch 40 is first closed, and then trigger switch 42 is closed. The .igger solenoid 44 is operated by current from switch 42 and the gun begins to fire. At the same time, solenoid 46 is energized, breaking the ground of relay 26 at switch 30. i

When the ground of relay 26 is broken at switch 30, there is atendency for thesolenoid of the relay 2%; to release the bell crank I I8, closing switches 34 and I20. Relay 26 is, however, a slow release relay of any suitable time period greater than the period of automatic fire of the gun 2|. Due to this characteristic, relay 26 will hold the bell. crank H8 until its time period has elapsed, in the absence of an intervening charging current. Relay 26 is intermittently grounded, however, through actuator switch 38, and the bell crank I it is thereby held to keep switches 34 and I2Il in an open condition, preventing the operation of master valve I8 and selector valves IIB. Actuator switch 33 is intermittently closed by reciprocating breech bolt of gun 2i striking switch operator 38. At every shot of the gun 2I, the breech bolt reciprocates and as the time between shots is less than the period of the slow release relay 26, the solenoid of relay 26 will be reenergized before its release period has expired.

If one of the guns should jam during a firing period, the solenoid 2'! of relay 26 of the jammed gun becomes deenergized at the expiration of its release period, and the bell crank II 8 moves to close switches 34 and IZll, Selector valve I II] now opens, and the movement of its core I12 acts through bell crank IIB to close switch I I4, grounding the current through the solenoid of master valve I8 which then opens to line I 6. The opening of selector valve IIB opens a passage for fluid to flow from the line l9 into the charging cylinder 20. When master valve I8 is operated, high pressure fluid flows into line I9, and through the open selector valve I It] and into the charging cylinder 25] of the jammed gun, charging that gun by retracting its breech bolt for counter-movement, which action ejects the dud shell and inserts a fresh one. During this charging operation, the selector valve of the other gun remains closed, no fluid can enter its charging mechanism, and the gun continues to fire uninterruptedly. When the breech bolt reaches its most retracted position during the charging stroke, it acts on operator 36 to close the actuator switch 38, thereby grounding relay 26 and breaking the connection to selector valve III] and master valv I8. The charging mechanism exhausts its charging fluid and the gun is again ready for firing. If the trigger system is still in a firing position, the gun wiFl once more fire upon the breech bolt contacting the cartridge chamber.

Upon cessation of firing, solenoid 46 is cleanergized, allowing switch 30 to close and establishing a ground for relay 26 through switches ing stroke, it is desirable to continue the charging operation so that a fresh cartridge will be in the firing chamber for the next firing period and this operation is as follows. When the charging cycle is started just prior to the cessation of firing, switch 28 is opened, thereby breaking the ground circuit for relay 25 that is normally established upon cessation of firing. Relay 25 therefore remains deenergized, and switches 34 and I20 remain closed. When the breech bolt reaches the end of its charging stroke, it causes switch 38 to close thus grounding relay 2B, and causing switches 34 and I20 to open, allowing the charging fluid to return to exhaust. By this operation a fresh cartridge is placed in the firing chamber, and the gun is again ready for automatic fire when the trigger is actuated.

ure 2 is similar to that of Figure l, which operation has also been described.

Having described our invention it is not intended to be limited to the specific disclosure made. The hydraulic and electrical systems may be changed in many ways and yet fall within our invention. Any fluid could be used in place of a hydraulic fluid in the systems disclosed. The devices included in the system may have various different applications and still come within the scope of the invention. Nor is the invention limited in any way other than by the terms of the following claims.

We claim:

- 1. The combination with a gun having a reciprocable breech bolt, of a fluid motor mounted on the gun to retract the bolt, a piston in said fluid motor normally urged toward one end thereof, means for engaging the breech bolt for retracting the same upon movement of the piston toward the other end of the motor, means mounted at said other end of the motor for latching the bolt in retracted position, and means within said fluid motor and operative upon movement of the piston toward the said other end of the motor to control the latching means to latch the bolt in retracted position and operative upon movement of the piston toward the said one end or the motor to release the latching means.

2. The combination with a gun having a reciprocable breech bolt, of a fluid motor mounted on the gun to retract the bolt, 2. piston in said, fluid motor normally urged toward one end thereof, means for engaging the breech bolt for retracting the same upon movement of the piston toward the other end of the motor, means mounted at said other end of the motor for latching the bolt 1 in retracted position, and latch controlling means Th armorers charging operation by pulling on ring 23 is similar to that of Figure 1 which has disposed within the motor and including a twoway lost-motion connection with the piston'and operative upon movement of the piston toward the said other end of the motor to control the latching means to latch said bolt and operative upon movement of the piston toward the said one end of the motor to control the latch means to release the bolt.

3. The combination with a gun having a reciprocable breech bolt, of a fluid motor mounted on the gun to retract the bolt, a piston in said fluid motor normally urged toward one end thereof, means for engaging the breech bolt for retracting the same upon movement of the piston toward the other end of the motor, means mounted on the motor for latching the bolt in retracted position, and means slidably mounted within said fluid motor and operative upon movement of the piston to the said other end of the motor to control the latching means to latch the bolt in retracted position and operative upon movement of the piston to the said one end of the motor to release the latching means.

4. A mechanism for retracting the breech bolt of a gun comprising a cylinder, a piston in the cylinder, said piston being normally urged toward one end of the cylinder and arranged for reciprocation therein, means for engaging the breech bolt for retracting the same upon movement of the piston toward the other end of the cylinder, means mounted on the cylinder for holding the breech bolt in a, retracted position, and means slidably mounted in the cylinder and operative upon movement of the piston toward the said other end of the cylinder to control the holding means to hold the bolt in retracted position and operative upon movement of the piston toward the said one end of the cylinder to release the holding means.

5. A mechanism for retracting the breech bolt of a gun comprising a cylinder, a piston in the cylinder, said piston being normally spring urged toward one end of the cylinder and arranged for reciprocation therein, means for engaging the breech bolt for retracting the same upon movement of the piston toward the other end of the cylinder, a latch means mounted on the cylinder for latching the breech bolt in retracted position, and latch controlling means carried by the cylinder and slidably mounted with respect thereto and operative upon movement of the piston toward the said other end of the cylinder to control the latch means to latch the bolt in retracted position and operative upon movement of the piston toward the said one end of the cylinder to release the latch means.

6. A mechanism for retracting the breech bolt of a gun comprisin a cylinder, a piston in the cylinder, said piston being normally urged toward one end of the cylinder and arranged for reciprocation therein, means for engaging the breech bolt for retracting the same upon movement of the piston toward the other end of the cylinder, means mounted on the cylinder for holding the breech bolt in a retracted position, and means carried by the cylinder and operative upon movement of the piston toward the said other end of the cylinder to control the holding means to hold the bolt in retracted position and operative upon movement of the piston toward the said one end of the cylinder to release the holding means.

'7. In a mechanism for retracting the breech bolt of a gun, a cylinder, a piston in the cylinder arranged for reciprocation, means for engaging the bolt for retracting the same upon movement of the piston in one direction, a latch member mounted on the cylinder and constructed and arranged for holding the bolt in retracted position, and latch controlling means slidably disposed within said cylinder and operative upon movement of the piston in said one direction to control the latch member to latch the bolt in retracted position and operative upon movement of the piston in the opposite direction to release the latch member.

8. The combination with a gun having a reciprocable breech bolt, of a fluid motor mounted on the gun to retract the bolt, a piston in said fluid motor normally urged toward one end thereof and constructed and arranged to engage the breech bolt to retract the same when said piston is moved toward said other end of the motor, means mounted on said other nd of the motor for latching the bolt in retracted position, and means Within said fluid motor and operative upon movement of the piston to the said other end of the motor to control the latching means to latch the bolt in retracted position and operative upon movement of the piston to the said one end of the motor to release the latching means.

9. A mechanism for retracting the breech bolt of a gun comprising a cylinder, a piston in the cylinder normally spring urged toward one end of the cylinder and arranged for reciprocation therein, means carried by the piston to engage the breech bolt to retract the same upon movement of the piston to the other end of the cylinder, means mounted on said other end of the cylinder for latching the bolt in retracted position, and means within said cylinder for controlling said latching means and including a member constructed and arranged to be extended from the said other end of the cylinder after the piston has retracted the breech bolt to latch the bolt in retracted position and to be withdrawn into said cylinder after the piston has returned to its normal position to release said latching means.

10. A mechanism for retracting the breech bolt of a gun comprising a cylinder, a piston in the cylinder normally urged toward one end thereof, means secured to the piston to engage the breech bolt to retract the same upon movement toward the other end of the cylinder, means mounted on said other end of the cylinder for latching the bolt in retracted position, a member in said cylinder constructed and arranged to be actuated by the piston to control said latching means, said member having a portion extendable from the end of the cylinder to engage said latching means to latch the bolt in retracted position after the piston has been moved to the said other end of the cylinder and a portion engageable by the piston to Withdraw said extendable portion into said cylinder after the piston has been moved to the said one end of the cylinder to disengage said latching means to unlatch the bolt.

11. A mechanism for retracting the breech bolt of a gun comprising a cylinder, a piston in the cylinder, said piston being normally spring urged toward one end of the ylinder and arranged for reciprocation therein, means for engaging the breech bolt for retracting the same upon movement of the piston toward the other end of the cylinder, a latch member mounted on the cylinder and constructed and arranged for latching the breech bolt in retracted position, and latch controlling means slidably mounted in the cylinder and operative upon movement of the piston toward the said other end of the cylinder to operate the latch member to latch the bolt in retracted position and operative upon movement of the piston toward the said one end of the cylinder to release the latch member.

GEORGE W. PONTIUS, III. ARTHUR P. WILSON. 

